Are laptop hard drives interchangeable?

I am looking for a cheap, small size laptop on ebay and I am considering the Thinkpad T60-2007. It does not come with a hard drive but I want to install one from a Windows 7 Dell laptop, and possibly install Linux at a later point. Would this work? I have the driver discs from the Dell. The Dell one is 2.5", SATA HD and I believe the T60 is also.

Depends. Is it a full OEM copy or is it just a image? Most likely it's an image complete with all the junkware that typically comes on a boxed PC. So trying to load it on to a different PC won't work since it's set up to work with the original PC's hardware. So when you start the system up windows will detect different hardware and tell you to contact microsoft or tell you it's not a genuine MS product and tell you to get a new copy of Windows.

It came with the dell laptop so it's probably an image. If I install Linux on the dell, then put the HD in the new laptop, could that work? What happens if I put the Dell version of Windows 7 in a different brand laptop?

When you install an OS it sets up drivers and everything for the hardware of that system. While you can transfer a linux install from one system to another you'll have a heck of a time getting everything reconfigured so it will run properly on the new system. Unless that new system has the exact same hardware as the old. In the case of Windows MS ties the install to the hardware configuration of the PC it was installed on. If it detects too many changes it locks you out and forces you to get a new copy of windows.

It's best if you install the OS on the comouter you intend to run it on.

Should I wipe the HD clean (using dban) and then insert it into the new laptop? Would I then use the Dell windows 7 disc in the new computer? Shou I make a disc with the drivers specific to the new laptop? I'm finding lots of different answers in the internet so I am somewhat confused.

The HDD will need to be wipe either before installing it into a new system or while the OS is being installed. Most OSs give you the opportunity to clear space on the drive to make room for the new OS. You won't be able to use the dell win7 disk in the new PC. Like i said before that disk is likely tailored for the hardware in the Dell laptop and won't work with a different hardware configuration. If you want Windows on the system you'll need to spend the $100 on a new OEM copy of Windows. The new OS will install the needed temporary drivers. Then you'll want to go to the manufactures web site of the new laptop and download the specific drivers for the system. Mainly you'll only need to get the right video drivers. Windows pretty much takes care of the rest.

Thanks for clearing that up. I think i will completly clean it off and install Linux before I put it in the new laptop. Should I make a usb or disc that has the drivers specific to whatever laptop I get eventually?

Aparently it didn't clear that up for you. Installing Linux on the old computer will cause problems when you move the drive to the new computer. When installed Linux will be using drivers for the old computer that won't be compatible with the new computer's hardware. Clear the drive, move it to the new PC and then install the OS.

Asuming the new laptop works yes it will work. Install the HDD, pop the disk into the Optical drive, In the bios tell the system to boot from the disk or if you put it on a thumb drive boot from USB device and your good to go.